7-amino and 7-hydroxy-1, 3, 4-triazaindolizines as stabilizers for photographic silver-halide emulsions



Sept. 14, 1948. N, HEIMBACH E -r AL 2,449,225

7AMIN0 AND 7HYDRoxY-1,,ll-TRIAZAINDOLIZINES As STABILIZERS- FOR PHoToGRAPHIc SILVER-HALIDE EMULsIoNs Filed 0013. 224, 1946 2 y y COLLO/DAL LAYE/2 7 con/TA f/v//va A 7 HYpeOxY-- SUPPORT COLLO/DAL LAYER IN V EN TOR.

NEWTON HE/MAcH WALTEE KELLY Je.

liatentecl Sept. i4,

"/-AMiNo AND v nYDRoXY-iA-'raiA-ZAIN- Domaines As s'rAeiLizEi-es Foa moroeaArHie simpa-Hamon EMULsIoNs Newton Hernbaeh and Walter Kelly, Jr., Binghamton, N. Y., aseignors to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Application October 22, 1946, Serial No. '704,933

This invention relates to the stabilizing of lightsensitve silver-halide emulsions, and more particularly to the use of reaction products obtained by the condensation of a -keto ester with a 3- amino-5-carbalkoxy-1,2,4-triazole as stabilizers for silver-halide emulsions.

It is known in the art that light-sensitive emulsions, such as gelatin silver-halide emulsions, have a decided tendency to fog. The fog may be of two types, namely, yellow fog and chemical (gray) fog. The yellow fog, sometimes referred to as color fog or dichroic fog, is'essentially a colloidal deposit of silver, the color intensity and general appearance of which are determined by the minute particle size and degree of subdivision. The fog is chiey yellow in color and is mostapparentin the lighter portions cfa negative. The color may vary, however, andthe colloidal silver particles may, for exampleappear green by reiiected light and yellow or red transmitted light. The so-called chemical frog, or gray A l2 Claims. (C1.95-7) fog, on the other hand, is the more common and The primary object ofthe present invention is to provide stabilizers or fog inhibiting agents which tend Ato prevent the formation of `chemical fog Yin light-sensitive silver-,halide emulsions.`

A further object 'is to provide stabilizers or anti-flogging agents for light-sensitive `silverhalide emulsions, which do not lower the sensitivity of the emulsion, and which increase its stability.

Still further objects and advantages will appear from the following specificatie We have found that the above objects are accomplished by the ruse of a reaction product obtained by the condensationnof a -keto ester with a 3-amino-5-carbalkoxy-1,2,4-triazole. sulting `condensation product is characterized by a structure corresponding-to the following general formula:

'wherein R is a carboxy or lcarbalkoxy group, e.` g., ycarlzvomethoxy, carbethoxy, carbopropoxy, and the I1ike,.`r't1 is an alkyl group, e; g., methyl, ethyl,

The reetc., aralkyl, e. g., benzyl, etc., heterocyclic e. g., pyridyl, furyl, pyrryhand the like, R2 isweither hydrogen, or an alkyl, aryl or aralkyl group of the same value as R1, and Y is an amino or hydroxy group.

The method for the preparation of the 7-hydroXy-1,3,4-triazaindolizines by condensing a keto ester with a 3-amino-1,2,4triazole is given in Berichte 42, 4643 and 43, pages 378-380. By substituting a 3-amino5carbalkoxy 1,2,4-triazole for the 3amino-l,2,4triazole.and employing the same reaction conditions described in these references, the hydroxy-LSA triazaindolizines utilized in accordance with this invention are readily prepared. By substituting /3- imino nitriles for the -keto ester and a S-amino- 5-carbalkoxy-1,2,4-triazole furthe 3-amino1,2,4 triazole and employing the same reaction conditions described in those references, the`7-aminc- 1,8,4-triazaindolizines utilized inaccordance with this invention are readily prepared. The method employed consists of heating l mol of a -keto' ester or 1 mol of a -imino nitrile with l mol of 3-amino--carbalkoxy-1,2,4-triazole of the following general formula:

Ra-/INH 4 a N=CNH2 wherein R3 is a carbalkoxy group of the same` value as that referred to above in defining character R.

Suitable -keto esters are, for example, ethyl acetoacetate, ethyl benzoylacetate, ethyl-a-ethyl acetoacetate, ethyl a-allyl acetoacetate, ethyl toluylacetate, ethyl propionylacetate, ethyl bu.- tyrylacetate, ethyl valerylacetate, ethyl nicotineacetate, and the like. l u

As suitable -imino nitriles may be mentioned, ,B-imino-butyronltrile, -phenyl--imino-propionitrile, -imino-a-methyl-butyronitrile, Iil-immoa-phenyl-butyrontrile, and the like.

As suitable` B-amino--carbalkoxy 1,2,4-triazoles may be mentioned, -amino--oarbometh- Oxy-1,2,4-triazole, 3 amino-5-carbethoxy-1,2,4 triazole, 3-amino-5-carbopropoxy-1,2,4 triazole, and the like. 'l

The condensation between the -keto ester and the S-amino-5-carbalkoxy-1,2,4-triazole, is carried out by heating the reaction components at i a ltemperature ranging from 100-120 C., pref- ;propyl, butyl, amyl, etc.,.ary1, e. g., phenyl, tolyl,

erably at reux temperature, in the presence of an inert water-binding, solvent-diluent, ksuch as glacial acetic acid, and the like, for a period of from 1 to 6 hours. The final product either precipitates or is removed by diluting `the solvent- 3 4 diluent with water, ethyl ether, acetone, or the (8) DITE: like, and is recrystallized from alcohol, e. g., G methanol, ethanol, ete., or alqohol-Water 11113-` Bo \N N ture. Y f

The -keto esters and the 3-amino-5-car- 5 l /C-,COoCzHs ba1koxy-1,2,4triazo1es are well-known to the,A HG C=N art and the methods for their prepelretionheed N/ not be described herein. l

Specific Compounds which hau/ieA nner-)aged 7.am 1no5-methyl-2-carbethOxy-1,3,4-tr1azamdo11zme in accordance with the above'pocedures, 'with l0 (9)- lfm their formulas, are the following: C

// (1) 0H E Io N-N` i C-cooczH C-C 0002EA @y gli;

35 Y'flqiriQ-f [2,1pyrdy11;21crheh0xy1ietriazaindqiiggnarr Thefollowing` examplee areVv intendedv to illugq trateethepreparation of"1 thecompounds di'gclosed above.

Example I1 0H 7-hydroxy-5-ethy1-2-carbomethoxy-L3,4-triazaindo1izne alliages form of long white needles from 150`cc. of boiling water. l f

Example III on /C nc/ \N-N\ l l c-o o o 02H i `7-liydroxy-5-phenyl-2carbethoxy-l,3,4-triazaindolizine Example I was repeated with the exception that an equivalent quantity of ethyl benzoylacetate was substituted for ethyl acetoacetate.

In the preparation of an emulsion containing the stabilizers used according to our invention, a solution of the stabilizer in a suitable solvent, such as alcohol or an alcohol-water mixture, adjusted to a neutral orslightly alkaline pH, i. e., pH 7 to 10, is made up and the solution mixed with the emulsion at any point during its preparation, but preferably during ripening or just prior to coating in concentrations varying from mg. to 500 mg. per liter of emulsion. The actual concentrationemployed will depend upon the type of emulsion used and varies slightly with thev compound used.

The method of testing the stabilizers in the following lexamples consists of coating two film strips such as cellulose acetate, with the same emulsion, one with and one without stabilizer, storing the emulsions in an incubator `for six days at 50 C., then exposing, developing, xing, and washing the same under standard conditions. The fog density or blackening produced in the unexposed areas in the two emulsions is then measured in a transmission densitometer of standard type.

The following examples will serve to illustrate certain ways in which the stabilizers of our in- ,vention have been applied, but are not to be construed as limiting the invention.

` Example IV Eample V Example IV was repeated with the exception that an equivalent quantity of the compound of Example II was substituted for the compound of Example I. The results obtained were almost identical with those obtained in Example IV.

Example VI Example IV was again repeated with the exceprtion that an equivalent quantity of the compound 'of Example III was substituted for the compound j of Example I. After incubation and development,

the emulsion containing the compound of Example III gave a fog of 0.1`.

Further experiments have shown that emulsions eontaining stabilizers in accordance with our invention have not only improved keeping qualities (i. e., a reduction in thelfog produced by incubation or by long storage) but in addition show little or no loss in speed to which some emulsions are susceptible. l f

The stabilizers, whichwe have described and employed, `may be used in various kinds of emfulsions. In addition to being useful `in `orthochromatic and panchromatic emulsions, they may also be used in non-sensitized emulsions and X-ray emulsions. If used with sensitizing `dyes they may be added to the emulsion before or after the dyes are added. The dispersing agents for the silver-halides may be gelatin or other colloid such as water-soluble cellulose derivatives, e. g., hydroxy ethyl cellulose, methyl cellulose, carboxy-oxy-cellulose, low acetyl value cellulose acetate, polyvinyl alcohol, and the like. The stabilizers may also .be employed in gelatin or other colloid, such as polyamides or a mixture of gelatin with a polyamide as described in United States Patent 2,289,775; polyvinyl alcohol and jelling compound as described in United States Patent 2,249,537; polyvinyl acetaldehyde acetal resins and partially hydrolyzed acetate resins described in United States Patents 1,939,422 and 2,036,092; cellulose derivatives e. g., cellulose nitrate, cellulose acetate, and the lower fatty acid esters of cellulose including simple and mixed esters and ethers of cellulose, and the like, as an under or overcoat for the emulsion or as a backing layer for the support. `Moreover, they may be incorporated in the support for the sensitive emulsion layer or in an intermediate layer betweenthe sensitive emulsion layerand the support, such as the baryta coating commonly used in photographic papers, or they may be incorporated in a protective layer coated upon the emulsion surface. Furthermore, the otherwise finished photographic material may be bathed in an alcohol or alcohol-water solution containing the stabilizer.

In the accompanying drawing the various iigures are enlarged section views 4of photographic materials having anti-fogging llayers made according to our invention.

Ik shown in Figure 1, the support I, which may be of any suitable material such as glass, cellulose ester, synthetic resin, or paper, is provided with an anti-fogging layer 3, containing one of said aminoor hydroxy-1,3,4-triazaindolizines referred to above. The light-sensitive emulsion layer 2 is attached to the anti-fogging layer 3. A

Figure 2 illustrates a similar material in which the support I is coated with a light-sensitive emulsion layer 2, and on thelatter side there is provided an anti-fogging layer 3, containing one of said aminoor hydroxy-1,3,4-triazaindolizines.

Figure 3 illustrates a film or plate of which the support I, bears on one side the light-sensitive emulsion layer 2 and on the other side an anti-fogging layer 3, containing such aminoor hydroxy-1,3,4-triazaindolizines.

Figure 4 illustrates a film, plate, or paper of which the support I is provided with the lightsensitive emulsion layer 2, containing as an antifogging layer aminoor hydroxy-1,3,fl-triazaindolizines.

Since the presence of these new compounds tends to prevent chemical fog whether they are incorporated directly into the emulsion, added toa separate surface or substratum` layer, .it is understood that "the` term lphotographic matenar-was employed herein and the. appended. cla used in aeeneriosanse o-.includeaaah; ett se possible applicati Marions V rnoci-tatiorls. Qfr his invention wilt occur to persons skilled in tl;1,earti-anti,itSJhere-A fore, understood that the. `n lent. er ated Shall onlnbe .limited :im the appended; Claims.-

.1. .A photographic material comprising-.abmeand; a ,light-sen.sitiye silver-halide. emulsion carried. thereby.. said-photographie material4 oon-f taining.. in fog V.inhibiting amount, a. Compound, of .the general formula;

wherein R, is a member selected-.from the class consisting of carboxy and carbalkoxy groups, R1

Y isa member selected from the classconsisting of alkyl, aryl,` and heterocyclic groups, R2 is a member selected from theclass consisting of hydrogen, alkyl, andaryl groups,V andY represents the member selected from the class consisting of., amino andhydroxy groups.

2. A photographic material. comprising a base and a light-sensitive` silver-halide ,emulsion carried thereby, said photographic material containing, in fog inhibiting amount, a compoundof the formula:

3. A photographic material comprisingl a base and: a light-.sensitive silverfhalde. emulsion carried thereby, saidphotognaphic material oontaining, in Afog inhibiting. amounua compound of the formula:

(lili o HC N*N Cv-C, QQH

H3C-e o=N 4, A photographic material. .comprising a4 base Y e .andY a'light-sensitivey slverfhalide emulsion carpied thereby, said photographie material. containingwin4 fog inhibiting amount, acompoundof the formula:

5. A photographic material., cQmprisi-ngabase vandl a light-.sensitive silver-halide; emulsion con- 8^. taining, fog: inhibiting; amounts e com the general formula:

7. A photographic material comprising abase and a light-sensitive silver-halide emulsion oontaining, in fog inhibiting amount, a compoundy of the formula:

8. A p-hotographiomaterialj comprising ,abase 3 and a light-sensitive silver-halide emulsion containing, in fog inhibiting amount, a compound of the formula:

l Ce-COOCzHs @e CN/ 9. A photographiegelatino silver-halide; emulsion containing from about 25- mg.. to aboutf500 mg. per liter of emulsion ofa eo'mpoundfofthe general formula:

wherein R is a memberv selected from tireclass ,Consisting of; carboxy and: arbalkoxral" lipsggRl is a memberse1ected,from the. c1as's,-conslis` n gsof an alkyl, aryl, andfheteroyolio,groups,.., sla member selected from the .class consisting Yo hydrogen, alkyl and; aryl groups,..andg.Ylre pre sents the member selected from the class, lQonsisting of amino and hydroxy groups.

9 u 10. A photographic gelatino silver-halide emulsion containing from about 25 mg. to about 500 mg. per liter of emulsion of a compound of the formula.:

(Im /C\ Ho/ N-N l C-COOCzHl HzC- /C=N \N 11. A photographic gelatno silver-halide emulsion containing from about 25 mg. to about 500 mg. per liter of emulsion'of a, compound of the formula:

on /C\ Hc/ N-N\ \o-oooH Imc-o c=N NEWTON HEIMBACH. WALTER KELLY, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Heimbach Dec. 11, 1945 Number 

